• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.79-81
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• 1998

STATCOM can compensate industrial load's reactive power and filter the harmonic of nonlinear load's with the rapid dynamic response. In this paper, STATCOM is modelled to synchronous rotating coordinate by circuit dq transformation, and space vector PWM method is applied for broad voltage modulation. Also predict current controller is used for harmonic current filtering.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.419-422
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• 1998

This paper presents how to design speed control of wound rotor induction motors with slip energy recovery. The speed is limited at some range of sub-synchronous speed of the rotating magnetic field. The problem with speed control by adjusting resistance value in the rotor circuit reduces the efficiency of power, because of the slip energy is lost when it passes through the rotor resistance. The control system is designed to maintain efficiency of motor, where it recovers loss energy by returning it to the system to improve the efficiency. A new PI control method of adaptive control [1］,［13］is applied for the system with cascade type PI controller on the main loop to keep the speed constant and the internal loop to adjust the rotor appropriated current of the load provides the good transient response without overshoot.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.9
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• pp.600-608
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• 1988

Although the structure of brushless dc motor is similar to that of a Permanent magnet synchronous motor, its torque-speed characteristcis are the same as those of a permanent magmet dc motor. The brushless dc motor drive systemcomposed of power converter including inverter, rotor positioning sensor and controller has been investigated for the purpose of position control when the motor is fed by a current controlled voltage source inverter. The equivalent transformation of a brushless dc motor into an separately exited dc motor has been possible with the vector control (field oriented control) technique. It is shown in this paper that the position control of a brushless dc mitor can be done fairly accurately only using q-axis current.

• Proceedings of the KIEE Conference
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• 2007.04b
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• pp.134-137
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• 2007

LMTT(Linear Motor-based Transfer Technology) 시스템은 항만 컨테이너 이송장치의 자동화 시템으로 기술적 포화상태에 이른 AGV (Automated Guided Vehicle)의 대체 수단으로 제안되었다. 본 논문에서는 PMLSM (Permanent Magnetic Linear Synchronous Motor)을 기본 구조로 한 LMTT에서 발생할 수 있는 레일과 차체간의 인척력 변화와 다양한 부하 중량에 대한 시스템 내부 변수의 변동에 적응할 수 있는 제어기 설계에 초점을 두었다. 그렇게 됨으로써 제어시 큰 방해요소로 작용하는 마찰력에 의한 백래쉬 및 데드존을 최소화하여 속응성 및 정밀도를 향상시키고자 하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.205-209
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• 2006

A linear motor based transfer vehicle is significantly focused as transportation systems in marine terminals for the future. We propose a control method for the systems to hence mass reduction and propulsion effects at a starting point by using a lift-force mechanism. This method is newly based on a combined levitation-and-propulsion power by a lift and thrust force of a permanent magnet linear synchronous motor (PMLSM), which is carried out by a decoupled control. We exam that our proposed control largely compensates the vehicle weight, reduces friction effect of the system, and increases its velocity. Consequently, this result contributes numerous productivity and economical efficiency for the port systems.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.501-505
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• 2001

The parallel operation system of UPS is used to increase reliability of power source at critical load. But parallel UPS system has a few defects, impedance is different from each other and circulating current occurs between UPSs, due to line impedance and parameter variation, though controlled by the same synchronization signal. According to such characteristic of parallel UPS, balanced load-sharing control is the most important technique in parallel UPS operation. In this paper, a novel power deviation compensation algorithm is proposed. it is composed of voltage controller to compensate power deviation that be calculated by using active and reactive current deviation between inverters on synchronous d-q reference frame.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.11
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• pp.888-895
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• 1989

A novel model reference adaptive control (MRAC) scheme for electrical servo drives is proposed, in which the control input is synthesized without any parameter identification mechanism and a PI controller is inserted ahead of the plant to reduce the steady state chattering. The proposed scheme is shown to be asymptotically stable in the case where the load torque disturbance satisfies a certan condition. An application to a permanent magnet synchronous motor drive shows that the output error between the plant and the reference model tends to zero and the chattering is greatly reduced.

• Proceedings of the KIEE Conference
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• summer
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• pp.1082-1084
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• 2004

This paper presents simulation and test results of PMSM(Permanent Magnet Sychronous Motor) Controller. PMSM has higher efficiency and torque per volume than other motors because PMSM use permanent magnet of high energy density instead of field winding. PMSM control system also more efficient than Induction Motor's. In this paper, simulation and test to control speed and current of PMSM using DSP was accomplished.

• Journal of Power Electronics
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• v.15 no.1
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• pp.116-122
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• 2015

This paper presents a new current sharing control strategy for parallel-connected, synchronised three-phase DC-AC converters employing space vector pulse width modulation (SVPWM) without current sharing reactors. Unlike conventional control methods, the proposed method breaks the paths of the circulating current by dividing the switching cycle evenly between parallel connected equally rated converters. Accordingly, any inter-module reactors or circulating current control will be redundant, leading to reductions in system costs, size, and control algorithm complexity. Each converter in the new scheme employs a synchronous dq current regulator that uses only local information to attain a desired converter current. A stability analysis of the current controller is included together with a simulation of the converter and load current waveforms. Experimental results from a 2.5kVA test rig are included to verify the proposed control method.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2268-2270
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• 2003

In this paper, mathematically modeled equations were derived for wind turbine under the analysis of aerodynamics. On the basis of these equations, maximum power controller is implemented by simulink in matlab. In order to achieving maximum power, variable speed control method is used for obtaining maximum power coefficient in the variable wind speed because we can have maximum changing efficiency in these coefficients. Also, the maximum power control of wind generator system uses a synchronous generator and a invertor circuit.